Why is it so hard to set MSFD indicators and targets? Messages from the plankton Climate change is causing unprecedented basin-scale ecological changes in our seas. At the same time, marine ecological systems are also responding to human pressures such as fishing, nutrient loading and hydrological changes. How can we develop indicators and targets which respond account for these varying pressures? What are some of the challenges facing scientists and policy makers during the Marine Strategy Framework Directive implementation process? How can information from the Continuous Plankton Recorder survey help?